Uncut detecting method in gas working

ABSTRACT

This invention provides a method for detecting &#39;&#39;&#39;&#39;uncut&#39;&#39;&#39;&#39; condition in gas workings, in particular in cutting works. The detection is performed by making use of two back pressures generated by pressurized fluid ejected from a jet located adjacent a nozzle and different with whether the gas from a nozzle is in a flame flow or a noncombustion flow.

0 United States Patent 1111 3,619,301

[ 72] Inventors Roku Suzuki; [56] References Cited Hidetaka Shigeizumi, both of Tokyo, Japan FOREIGN PATENTS [21] A I. No. 810,961 [22] i Man 27, 1969 4,227,546 12/1967 Japan 148/9 [45] Patented Nov. 9, 1971 Primary Examiner-Delbert E. Gantz [73] Assignee Koike Sanso Kogyo Co. Ltd, Assislan! Examiner-C. E. Spresser T k Ja n Attorney-Cohen and Stone [54] UNCUIr DETECTI.NG METHOD [N GAS WORKING ABSTRACT: This invention provides a method for detecting 11 Claims, 3 Drawing Figs. u

uncut condmon 1n gas workmgs, 1n particular 1n cuttmg [52] US. Cl 148/9 works. The detection is performed by making use of two back [5 i] B23k 7/00 pressures generated by pressurized fluid ejected from a jet [50] Field of Search 148/9; located adjacent a nozzle and different with whether the gas 266/23 from a nozzle is in a flame flow or a noncombustion flow.

PATENTEDuuv 9 I97! 8.619.301

INVBNTORS KOKU SUZUKI HIDETAKA SHIGEIZUMI ATTORNEYS UN CUT DETECTING METHOD IN GAS WORKING BACKGROUND OF THE INVENTION In gas working, for instance in gas cutting, flames coming from the cutting gas from a nozzle will flow straight through a workpiece (such flow is hereinafter referred as flame flow A) in normally performed cuttings. However, if there occur any undesirable changes in course of the working, such as an excessively high cutting speed, irregular change in the pressure or the flowing quantity of the fuel gas or oxygen (hereinafter such are referred to as gas); extinction of the flame would occur nonnal cutting would not be realized thus causing a futile flow of the gas which flows laterally from the nozzle along the surface of the workpiece after it has once impinged thereto in a flame flow (this flow is hereinafter referred as flame flow C) or in a gas flow (noncombustion gas flow; such flow is hereinafter referred as flow D). This phenomenon is generally called uncut" in gas working. It is apparent that the establishment of a suitable detecting method for the uncut" situation will yield a great increase of working efficiency to gas working, but heretofore neither such a suitable method nor apparatus has been disclosed in connection with the detecting art.

SUMMARY OF THE INVENTION This invention relates to a method detecting an abnormal working state in gas working and more particularly to the same detecting the uncut situation in relation to said flame flow C or gas flow D.

In the invention, a pressurized fluid, such as compressed air, is caused to eject from a jet located in the vicinity of the top of a nozzle and the pressure of the compressed air is previously adjusted to be in such a balanced state that there is no atmospheric pressure change in the surroundings of the jet, i.e., no back pressures thereabout in the normal working condition. Now assume that the gas from the nozzle ha's changed into the flame flow C, presenting an uncut state. Then the compressed air ejected from the jet will impinge against the flame fiow C and will expand with high heat thereof to flow rapidly in lateral directions with the flame flow C along the surface of the workpiece, thus a negative pressure will be, as a corollary, generated over the surroundings'of the jet. Assume further that the gas flow from the nozzle has turned into a gas flow D (a noncombustion gas flow). The compressed air from the jet will generate a turbulent flow with the gas flow D because it presents no high heat reactions in this case and as a consequence a positive pressure will prevail over the surroundings of the jet.

The major object of the present invention is to provide a method capable of detecting simply and precisely the uncut" condition by means of making use of said negative or positive pressures.

To the apparatus embodying the invention, a device for generating electric signals is preferably in use, which is activated by the negative or positive pressures conducted into through a line having a detecting port located adjacent a nozzle.

DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic view of one embodiment of the invention wherein an uncut state is shown;

FIG. 2 is a diagrammatic view almost like that shown in FIG. 1 wherein a normal working situation is shown;

FIG. 3 is an enlarged partially sectional elevation of FIG. 2 wherein an uncut" state is depicted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the FIGU RE, 3 is a body member having bore 4 into cut" situation by ejecting a compressed air from jet 2 opening adjacent port 6. The compressed air is fed to jet 2 through path 7. Detecting port 6 is communicated with pressure switches 9 and 10 through line 8 which will preferably assume the form of tasimetric switch. Line 8 transmits the negative or positive pressure of said back pressure from port 6 to the switch 9 or 10 respectively. Pressure switch 9 will be actuated only by the negative pressure at detecting port 6 while switch 10 by positive pressure at the same.

In said constitution, when a cutting work is normally carried out as the compressed air is introduced into from path 7 to eject from jet 2, flame flow A will be in a state shown in FIG. 2 without actuation of the pressure switches because the pressure at detecting port 6 is equivalent to the atmospheric pressure as set forth above. Assuming said working to turn into an abnormal one to change the flow into the state C shown FIG. 3, the compressed air from jet 2 will impinge against the flame flow C to be heated with high heat thereof thus expanding rapidly to flow out laterally with high speed with the flame flow C along the surface of workpiece 11, as a corollary of which'a negative pressure will be generated at detecting port 6, which causes pressure switch 9 to actuate through line 8.

When the flame flow changes into an extinct condition or noncombustion gas flow D, the compressed air from jet 2 will generate a turbulent flow with gas flow D to generate a positive pressure at detecting port 6 because the compressed air will not present such the high heat reaction as in the prior case. This positive pressure will causes pressure switch 10 to actuate through line 8. Accordingly, the uncut and normal states of the working may be known with ease by means of adapting those switches to generate the output signals based on the input back pressures.

Some concrete numerical values of the back pressures at the detecting port presented in an embodiment of the invention will be shown as follows:

I. When gas is in flame flow C -50 (mercury, mm.)

2. When gas is in noncombustion flow D+l00 (mercury, mm.)

The compressed air of 3.5 kg.-/cm. was used in this case.

As mentioned above, this invention has a great feature in that different back pressures are caused to generate with whether the gas from a nozzle, a working tool, is in flame flow C or in gas flow D, whereby the uncut" state may be detected by the analyzed two back pressures. Therefore, as an appropriate control devices are caused to activate by the electric signals from such device as said pressure switch, those will act for the performance of normal workings in gas work or other various like work.

We claim:

1. A method for detecting uncut state in gas cutting work characterized in that it comprises ejecting a pressurized fluid toward a workpiece at a point in the vicinity of a nozzle to cause it to generate different back pressures in response to whether the gas from the nozzle is in a flame flow or in a noncombustion gas flow; and detecting said different back pressures and thereby indicating the uncut state.

2. The method according to claim 1 wherein the pressure of the ejected pressurized fluid is previously adjusted to be in such a balanced state that there is no atmospheric pressure changes about the ejecting point in a normal working condition.

3. The method according to claim I wherein one of said different back pressures is a positive pressure and the other is a negative one.

4. The method according to claim 1 wherein a detecting port for detection of said back pressures and a jet for ejection of said pressurized fluid are formed in a body member having a bore into which the top portion of said nozzle is fixedly fitted.

5. The method according to claim 1 wherein the pressurized fluid is a compressed air.

6. The method of claim 1 wherein the pressurized fluid is ejected in an area, the pressure of which is affected by the gas from the noule.

7. A method of cutting a workpiece by a gas nozzle providing a first gas path through the workpiece when the workpiece is being cut and a second gas path along the workpiece when the workpiece is not being cut and detecting a uncut state comprising ejecting a pressurized fluid toward the workpiece adjacent the nozzle in an area, the pressure of which is affected by gas emitting from the nozzle; and

detecting a change of pressure in the area.

8. The method of claim 7 wherein the measuring 'step comprises detecting a change in pressure with respect to a predetermined datum.

9. The method of claim 8 wherein the predetermined datum is the pressure of the ejected pressurized fluid when the gas emitting from the nozzle is following the first path.

10. The method of claim 8 wherein the measuring step comprises detecting an increase in pressure over the datum to indicate noncombustion gas flow from the nozzle.

11. The method of claim 8 wherein the measuring step comprises detecting a decrease in pressure under the datum to indicate a flame flow. 

2. The method according to claim 1 wherein the pressure of the ejected pressurized fluid is previously adjusted to be in such a balanced state that there is no atmospheric pressuRe changes about the ejecting point in a normal working condition.
 3. The method according to claim 1 wherein one of said different back pressures is a positive pressure and the other is a negative one.
 4. The method according to claim 1 wherein a detecting port for detection of said back pressures and a jet for ejection of said pressurized fluid are formed in a body member having a bore into which the top portion of said nozzle is fixedly fitted.
 5. The method according to claim 1 wherein the pressurized fluid is a compressed air.
 6. The method of claim 1 wherein the pressurized fluid is ejected in an area, the pressure of which is affected by the gas from the nozzle.
 7. A method of cutting a workpiece by a gas nozzle providing a first gas path through the workpiece when the workpiece is being cut and a second gas path along the workpiece when the workpiece is not being cut and detecting a ''''uncut'''' state comprising ejecting a pressurized fluid toward the workpiece adjacent the nozzle in an area, the pressure of which is affected by gas emitting from the nozzle; and detecting a change of pressure in the area.
 8. The method of claim 7 wherein the measuring step comprises detecting a change in pressure with respect to a predetermined datum.
 9. The method of claim 8 wherein the predetermined datum is the pressure of the ejected pressurized fluid when the gas emitting from the nozzle is following the first path.
 10. The method of claim 8 wherein the measuring step comprises detecting an increase in pressure over the datum to indicate noncombustion gas flow from the nozzle.
 11. The method of claim 8 wherein the measuring step comprises detecting a decrease in pressure under the datum to indicate a flame flow. 